Stuck at 2400 RPM'S

[truax42]

Need help with my 89 Evinrude 120 V4...... Had this motor in the shop for a physical. Wrench done a spark test, compression test, (all tested good) new water pump and fuel pump. Finally got the boat on the water for the first time over the weekend. Idled great after it came up to temp but when i tied to come up on plane, i cant get anything over 2400rpm's. It just wont come up out of the hole. The throttle plates are opening all the way. It doesnt act like a spark problem because the motor stays at a smooth 2400, not like it is cutting out or anything. New plugs didnt help. Like I said, never been on this boat before so I dont know where to start now. Any ideas??<br /><br />Also on another topic, for some reason, i lost power to my tilt switch on the throttle and the front control panel near my trolling motor (boat is an 89 stratos fs279) tried tracking that problem down and cant find anything here either. any help on either or both is great

 

[Hooty]

Re: Stuck at 2400 RPM'S

Sounds like it's got one or two cylinders that aren't firing. I don't know if that engine has a shift interupter switch or not. That might be worth looking at. <br /><br />c/6<br />Hooty

 

[truax42]

Re: Stuck at 2400 RPM'S

not sure on the shift interupter. will check on that. could a coil or two be breaking down under load?

 

[truax42]

Re: Stuck at 2400 RPM'S

All cylinders are firing fine and not a thing wrong with the prop. any other advice?

 

[Daniel Beckman]

Re: Stuck at 2400 RPM'S

Could be the SLOW system that breaks in, maybe beacasue of a fault heat sensor or something else that controls the SLOW system.

 

[truax42]

Re: Stuck at 2400 RPM'S

you lost me on the slow system....can you explain?

 

[Daniel Beckman]

Re: Stuck at 2400 RPM'S

Well im not an expert, but the slow system will kill half the engine if its for example overheated.<br />Im sure someone else here could explain better and what else control the system.<br />Try to do a search for slow on here.

 

[truax42]

Re: Stuck at 2400 RPM'S

i took the carbs apart and found 4 jets plugged. after a good cleaning, i went back to the lake with the same problem. at wot, i can still get only 22-2400 rpms. i pushed the choke in and it started to come to life just briefly. where to now? <br /><br />another question is the jet size. i have a #41 and a #50 in each carb. not knowing they were numbered before removal, i have no idea if the 50 goes in the top or bottom jet opening. again this is a 1989 evinrude 120 v4.<br /><br />another possibility may be that i recently replaced the vro with a replacement fuel filter and run premix. there is a hose fitting on the bottom side of the pump that does not go anywhere (to my knowledge) so i blocked it off. did i do the right thing? there is a line coming into the pump from the tank and one going to the fuel tree for the carbs. should this extra belong somewhere?